Methods and apparatus for thrombectomy system

Abstract

In certain embodiments, the system is configured to remove from or fragment materials in a vessel by inserting a catheter into a vessel, wherein the distal tip of the catheter is placed at the surgical site and a liquid spray is applied to materials to remove or fragment (as defined herein) the materials. In certain embodiments, the system comprises a liquid spray emanating from a fragmentation lumen and across a fragmentation opening.

What is claimed is: 
     
       1. Apparatus for removing occlusive material from a blood vessel lumen, said apparatus comprising:
 a catheter shaft sized for insertion into said blood vessel, said shaft having a pressure lumen terminating in a nozzle and an evacuation lumen having a fragmentation opening adjacent said nozzle; 
 a liquid source configured for flowing liquid through said pressure lumen; and 
 a drive unit connected to said evacuation and pressure lumens and comprising:
 a pressure pump configured to deliver positive pressure impulses to said pressure lumen; 
 a suction pump configured to deliver negative pressure impulses to said evacuation lumen; and 
 a dual-piston actuator configured to drive the pressure pump and the suction pump to cause a cycling pressure pattern in which the positive pressure impulses in said pressure lumen alternate with the negative pressure impulses in said evacuation lumen; 
 
 wherein said nozzle of said pressure lumen is positioned relative to said fragmentation opening in said evacuation lumen such that occlusive material cut or fragmented by liquid spraying out of said nozzle in response to said positive pressure impulses enters said evacuation lumen through said fragmentation opening. 
 
     
     
       2. The apparatus of  claim 1  wherein said positive pressure impulses have a peak pressure of between 20 and 100 PSI. 
     
     
       3. The apparatus of  claim 2 , wherein said positive pressure impulses have a peak pressure of between 30 and 70 PSI. 
     
     
       4. The apparatus of  claim 1 , wherein said negative pressure impulses create a vacuum of 50 mmHg or greater in said evacuation lumen. 
     
     
       5. The apparatus of  claim 1 , wherein:
 said nozzle comprises a tapered nozzle portion configured to direct a liquid spray toward an interior portion of the catheter shaft. 
 
     
     
       6. The apparatus of  claim 5 , wherein:
 said catheter shaft further comprises a sidewall having a sidewall opening; and 
 said tapered nozzle portion is configured to direct the liquid spray alongside said sidewall opening. 
 
     
     
       7. The apparatus of  claim 5 , wherein:
 said catheter shaft further comprises a sidewall having a sidewall opening; and 
 said tapered nozzle portion is configured to direct the liquid spray alongside or through said sidewall opening and distally from said pressure lumen. 
 
     
     
       8. The apparatus of  claim 1 , wherein:
 said nozzle comprises a nozzle portion having a reduced luminal cross-sectional area relative to a proximal portion of said pressure lumen; and 
 said catheter shaft further comprises a sidewall with a sidewall opening; and 
 said nozzle portion is configured to deliver a liquid spray that passes alongside said sidewall opening. 
 
     
     
       9. The apparatus of  claim 1 , wherein said nozzle comprises a nozzle portion having a generally circular exit port. 
     
     
       10. The apparatus of  claim 1 , wherein said nozzle comprises a nozzle portion having an exit port with a flattened shape. 
     
     
       11. The apparatus of  claim 1 , further comprising a first check valve positioned between the liquid source and the pressure pump to permit only one way flow from the liquid source to the pressure pump. 
     
     
       12. The apparatus of  claim 11 , further comprising a second check valve positioned between a waste receptacle and said suction pump to permit only one way flow from the suction pump to the waste receptacle. 
     
     
       13. The apparatus of  claim 1 , wherein the dual-piston actuator is configured to vary a speed of the alternating between the positive pressure impulses and the negative pressure impulses based on whether material is detected in the evacuation lumen or within the fragmentation opening. 
     
     
       14. A method of removing occlusive material from a blood vessel, said method comprising:
 inserting an elongate shaft into said blood vessel, said shaft having a pressure lumen and an evacuation lumen; 
 causing, by a drive unit, a cycling pressure pattern to be applied to said pressure lumen and said evacuation lumen, whereby a positive pressure applied to said pressure lumen alternates with a negative pressure applied to said evacuation lumen, and wherein the drive unit comprises a pressure pump configured to deliver the positive pressure to the pressure lumen, a suction pump configured to deliver the negative pressure to the evacuation lumen, and a dual-piston actuator configured to drive the pressure pump and the suction pump to cause the cycling pressure pattern; 
 drawing a portion of said occlusive material toward said pressure lumen in response to the application of the negative pressure to said evacuation lumen; 
 emitting a liquid spray from said pressure lumen in response to the application of the positive pressure to said pressure lumen; and 
 fragmenting said portion of occlusive material with said liquid spray. 
 
     
     
       15. The method of  claim 14 , further comprising evacuating said fragmented material via said evacuation lumen. 
     
     
       16. The method of  claim 14 , wherein said liquid spray is emitted from said pressure lumen at a peak pressure of less than 100 PSI. 
     
     
       17. The method of  claim 16 , wherein said peak pressure is 30-50 PSI. 
     
     
       18. The method of  claim 14 , further comprising causing said cycling pressure pattern using a drive unit comprising a dual-piston actuator driving a pressure pump and a suction pump. 
     
     
       19. The method of  claim 18 , further comprising sealing said pressure pump using at least one check valve. 
     
     
       20. The method of  claim 19 , further comprising sealing said suction pump using a second at least one check valve. 
     
     
       21. The method of  claim 18 , further comprising sealing said suction pump using at least one check valve. 
     
     
       22. A method comprising:
 delivering liquid through a fragmentation lumen of an elongate shaft at a positive pressure of 100 PSI or less, the elongate shaft sized for insertion into a blood vessel; 
 emitting said liquid as a liquid spray from said fragmentation lumen; and 
 applying a negative pressure to said liquid spray via an evacuation lumen of said elongate shaft; 
 wherein the positive pressure applied to the fragmentation lumen alternates with the negative pressure applied to the evacuation lumen via a drive unit comprising a pressure pump configured to apply the positive pressure to the fragmentation lumen, a suction pump configured to apply the negative pressure to the evacuation lumen, and a dual-piston actuator configured to drive the pressure pump and the suction pump to cause a cycling pressure pattern applied to the fragmentation lumen and the evacuation lumen. 
 
     
     
       23. The method of  claim 22 , wherein said delivering comprises delivering said liquid at a peak pressure of 20-70 PSI. 
     
     
       24. The method of  claim 22 , wherein said delivering comprises delivering said liquid at a peak pressure of 30-50 PSI. 
     
     
       25. The method of  claim 22 , wherein said applying said negative pressure creates a vacuum of 50 mmHg or more. 
     
     
       26. The method of  claim 22 , further comprising evacuating material fragmented by said liquid spray via said evacuation lumen. 
     
     
       27. The method of  claim 22 , wherein said positive and negative pressures respectively applied to the fragmentation and evacuation lumens are created by a drive unit comprising a dual-piston actuator driving a pressure pump and a suction pump.